Runs online opinion polls on a variety of issues internationally. They have pools of people that they ask survey questions, and also pull in data from social media and other sources to help brands understand their image. They are starting to get into the audience segmentation business too. YouGov is quite large and has acquired a number of related companies.

Full-service political marketing company focused on European campaigns. They combined traditional campaigning techniques like canvassing with more advanced databases about voters, in particular their 50+ One voter database software. Their work seems to focus more on optimizing canvassing using data and campaign management rather than social media campaigns. They work on both political campaigns, as well as canvassing and surveys around political/social issues or for trade unions. Due to limitations on data available in Europe, they generally start with data at the neighborhood level rather than the individual level and collect additional data through door-to-door canvassing.

Major data broker that collects data from a wide variety of sources. They sell data and match up the identities of people across data sources. Acxiom also offers consulting services to help organizations use their data. They created a website (https://aboutthedata.com) that explains how targeted advertising works and offers to let people control how their data is used, but also likely collects data in the process.